Need Help! Whats happening??

I’m seriously weirded out I have had my ring for 4 months and this is the 3rd time this has happed. I go in the kitchen to wash dishes and cook and I ALWAYS take my ring off and put it in my little bowl. cook, clean eat and go to put my ring back on and this! it looks like mold right? it was in the bowl no more than 2 hours. I’m super carful about my ring. I don’t wear it washing dishes in the shower or working out. has this happened to anyone?